[Ocfs2-devel] [PATCH v2] ocfs2: fix ocfs2 read inode data panic in ocfs2_iget
Joseph Qi
jiangqi903 at gmail.com
Sun Apr 7 19:26:37 PDT 2019
On 19/4/2 14:18, Shuning Zhang wrote:
> In some cases, the function ocfs2_iget read the data of inode, which has
> been deleted for some reason. That will make the system panic. So We
> should judge whether this inode has been deleted, and tell the caller
> that the inode is a bad inode.
>
> For example, the ocfs2 is used as the backed of nfs, and the client is
> nfsv3. This issue can be reproduced by the following steps.
>
> on the nfs server side,
> ..../patha/pathb
>
> Step 1: The process A was scheduled before calling the function
> fh_verify.
>
> Step 2: The process B is removing the 'pathb', and just completed the
> call to function dput.
> Then the dentry of 'pathb' has been deleted from the dcache, and all
> ancestors have been deleted also.
> The relationship of dentry and inode was deleted through the function
> hlist_del_init. The following is the call stack.
> dentry_iput->hlist_del_init(&dentry->d_u.d_alias)
>
> At this time, the inode is still in the dcache.
>
> Step 3: The process A call the function ocfs2_get_dentry, which get
> the inode from dcache. Then the refcount of inode is 1. The following
> is the call stack.
> nfsd3_proc_getacl->fh_verify->exportfs_decode_fh->fh_to_dentry(ocfs2_get_dentry)
>
> Step 4: Dirty pages are flushed by bdi threads. So the inode of
> 'patha' is evicted, and this directory was deleted.
> But the inode of 'pathb' can't be evicted, because the refcount of the
> inode was 1.
>
> Step 5: The process A keep running, and call the function
> reconnect_path(in exportfs_decode_fh), which call function
> ocfs2_get_parent of ocfs2. Get the block number of parent
> directory(patha) by the name of ... Then read the data from disk by the
> block number. But this inode has been deleted, so the system panic.
>
> Process A Process B
> 1. in nfsd3_proc_getacl |
> 2. | dput
> 3. fh_to_dentry(ocfs2_get_dentry) |
> 4. bdi flush dirty cache |
> 5. ocfs2_iget |
>
> [283465.542049] OCFS2: ERROR (device sdp): ocfs2_validate_inode_block:
> Invalid dinode #580640: OCFS2_VALID_FL not set
>
> [283465.545490] Kernel panic - not syncing: OCFS2: (device sdp): panic forced
> after error
>
> [283465.546889] CPU: 5 PID: 12416 Comm: nfsd Tainted: G W
> 4.1.12-124.18.6.el6uek.bug28762940v3.x86_64 #2
> [283465.548382] Hardware name: VMware, Inc. VMware Virtual Platform/440BX
> Desktop Reference Platform, BIOS 6.00 09/21/2015
> [283465.549657] 0000000000000000 ffff8800a56fb7b8 ffffffff816e839c
> ffffffffa0514758
> [283465.550392] 000000000008dc20 ffff8800a56fb838 ffffffff816e62d3
> 0000000000000008
> [283465.551056] ffff880000000010 ffff8800a56fb848 ffff8800a56fb7e8
> ffff88005df9f000
> [283465.551710] Call Trace:
> [283465.552516] [<ffffffff816e839c>] dump_stack+0x63/0x81
> [283465.553291] [<ffffffff816e62d3>] panic+0xcb/0x21b
> [283465.554037] [<ffffffffa04e66b0>] ocfs2_handle_error+0xf0/0xf0 [ocfs2]
> [283465.554882] [<ffffffffa04e7737>] __ocfs2_error+0x67/0x70 [ocfs2]
> [283465.555768] [<ffffffffa049c0f9>] ocfs2_validate_inode_block+0x229/0x230
> [ocfs2]
> [283465.556683] [<ffffffffa047bcbc>] ocfs2_read_blocks+0x46c/0x7b0 [ocfs2]
> [283465.557408] [<ffffffffa049bed0>] ? ocfs2_inode_cache_io_unlock+0x20/0x20
> [ocfs2]
> [283465.557973] [<ffffffffa049f0eb>] ocfs2_read_inode_block_full+0x3b/0x60
> [ocfs2]
> [283465.558525] [<ffffffffa049f5ba>] ocfs2_iget+0x4aa/0x880 [ocfs2]
> [283465.559082] [<ffffffffa049146e>] ocfs2_get_parent+0x9e/0x220 [ocfs2]
> [283465.559622] [<ffffffff81297c05>] reconnect_path+0xb5/0x300
> [283465.560156] [<ffffffff81297f46>] exportfs_decode_fh+0xf6/0x2b0
> [283465.560708] [<ffffffffa062faf0>] ? nfsd_proc_getattr+0xa0/0xa0 [nfsd]
> [283465.561262] [<ffffffff810a8196>] ? prepare_creds+0x26/0x110
> [283465.561932] [<ffffffffa0630860>] fh_verify+0x350/0x660 [nfsd]
> [283465.562862] [<ffffffffa0637804>] ? nfsd_cache_lookup+0x44/0x630 [nfsd]
> [283465.563697] [<ffffffffa063a8b9>] nfsd3_proc_getattr+0x69/0xf0 [nfsd]
> [283465.564510] [<ffffffffa062cf60>] nfsd_dispatch+0xe0/0x290 [nfsd]
> [283465.565358] [<ffffffffa05eb892>] ? svc_tcp_adjust_wspace+0x12/0x30
> [sunrpc]
> [283465.566272] [<ffffffffa05ea652>] svc_process_common+0x412/0x6a0 [sunrpc]
> [283465.567155] [<ffffffffa05eaa03>] svc_process+0x123/0x210 [sunrpc]
> [283465.568020] [<ffffffffa062c90f>] nfsd+0xff/0x170 [nfsd]
> [283465.568962] [<ffffffffa062c810>] ? nfsd_destroy+0x80/0x80 [nfsd]
> [283465.570112] [<ffffffff810a622b>] kthread+0xcb/0xf0
> [283465.571099] [<ffffffff810a6160>] ? kthread_create_on_node+0x180/0x180
> [283465.572114] [<ffffffff816f11b8>] ret_from_fork+0x58/0x90
> [283465.573156] [<ffffffff810a6160>] ? kthread_create_on_node+0x180/0x180
>
> Changes in v2:
> - add description of reporducing this issue
> - use ocfs2_test_inode_bit instead of i_dtime
>
> Signed-off-by: Shuning Zhang <sunny.s.zhang at oracle.com>
Looks good to me.
Reviewed-by: Joseph Qi <jiangqi903 at gmail.com>
> ---
> fs/ocfs2/export.c | 30 +++++++++++++++++++++++++++++-
> 1 files changed, 29 insertions(+), 1 deletions(-)
>
> diff --git a/fs/ocfs2/export.c b/fs/ocfs2/export.c
> index 827fc98..da17aa6 100644
> --- a/fs/ocfs2/export.c
> +++ b/fs/ocfs2/export.c
> @@ -148,16 +148,24 @@ static struct dentry *ocfs2_get_parent(struct dentry *child)
> u64 blkno;
> struct dentry *parent;
> struct inode *dir = d_inode(child);
> + int set;
>
> trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
> (unsigned long long)OCFS2_I(dir)->ip_blkno);
>
> + status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
> + if (status < 0) {
> + mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
> + parent = ERR_PTR(status);
> + goto bail;
> + }
> +
> status = ocfs2_inode_lock(dir, NULL, 0);
> if (status < 0) {
> if (status != -ENOENT)
> mlog_errno(status);
> parent = ERR_PTR(status);
> - goto bail;
> + goto unlock_nfs_sync;
> }
>
> status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
> @@ -166,11 +174,31 @@ static struct dentry *ocfs2_get_parent(struct dentry *child)
> goto bail_unlock;
> }
>
> + status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set);
> + if (status < 0) {
> + if (status == -EINVAL) {
> + status = -ESTALE;
> + } else
> + mlog(ML_ERROR, "test inode bit failed %d\n", status);
> + parent = ERR_PTR(status);
> + goto bail_unlock;
> + }
> +
> + trace_ocfs2_get_dentry_test_bit(status, set);
> + if (!set) {
> + status = -ESTALE;
> + parent = ERR_PTR(status);
> + goto bail_unlock;
> + }
> +
> parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
>
> bail_unlock:
> ocfs2_inode_unlock(dir, 0);
>
> +unlock_nfs_sync:
> + ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1);
> +
> bail:
> trace_ocfs2_get_parent_end(parent);
>
>
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